Type and Screen versus a Type and Crossmatch

Type and Screen: The blood bank staff will perform all necessary testing on the patient's sample. Until a separate request is received for crossmatched blood, units will not be crossmatched and set aside in the blood bank for that patient. However, once a request for blood is received, crossmatched blood can be made available quickly.
This order should be used when the likelihood of the patient needing a blood transfusion is slight.

Type and Crossmatch: The blood bank staff will perform all necessary testing on the patient's sample AND crossmatch the number of units requested. In the blood bank, these units will be set aside for the patient and are immediately available once the physician determines there is a need to transfuse the patient..

Choosing: If the physician does not anticipate the need for a blood transfusion but the potential is there, a type and screen should be requested. A type and cross should be requested whenever a transfusion is expected or very likely. This is more important during periods of blood shortages. During these shortage periods, the blood bank staff may decide to not hold or crossmatch blood for a patient unless an order to transfuse has been received.

The Blood Sample

The blood sample from the patient must be no older than three days. If a blood sample is collected on Monday, that sample will be good until Thursday at midnight. Another sample for additional transfusions must be drawn Friday.

Blood Bank Testing:
All samples received for a type and cross or a type and screen are tested for:

ABO antigens and antibodies,

Rh(D) antigen, and the

presence of antibodies to different red cell antigens.

The latter is termed an antibody screen. There are over 400 known antigens that can be present or absent on Red Blood Cells. During a transfusion or pregnancy, patients may be exposed to different red blood cell antigens that may result in antibody formation by the patient. If these antibodies are not detected, they can destroy the transfused red blood cells. However, not everyone will form these red cell antibodies. Because it is difficult to determine who may have been exposed to other red cell antigens, all patient samples are tested or "screened" for these antibodies.